You might get a couple years (or more) recharging of the battery but after a while it won't hold a charge. Sounds like this is your situation. These are a common battery and can be found on Amazon and elsewhere for example: http://www.amazon.com/T-Lucent-AT3211-2-Cordless-Battery-Replacement/dp/B0083YBU5O
Answers & Comments
You might get a couple years (or more) recharging of the battery but after a while it won't hold a charge. Sounds like this is your situation. These are a common battery and can be found on Amazon and elsewhere for example:
http://www.amazon.com/T-Lucent-AT3211-2-Cordless-Battery-Replacement/dp/B0083YBU5O